Studies Show Cannabis Can Be Dangerous for Pets

Cannabis for pets is a very hot topic. While many have raised concerns about the rate of animals being brought in for cannabis overdoses increasing after legalization, others are intrigued by the promise of cannabinoid medicine for animals, with most of the interest on hemp or cannabis-derived CBD products.

Cannabis Now spoke to two veterinarians, Dr. Josh Sosnow, the CMO of Companion CBD, and Dr. Gary Richter, a veterinary health expert with Rover.com, as well as Julianna Carella, the founder of Treatibles, to better understand the benefits and potential risks of cannabis for our animal friends.

What Kinds of Pets Can Use Cannabis?

The endocannabinoid system has been found in mammals, birds, reptiles and fish. Evidence has even emerged of crude endocannabinoid systems in invertebrates, which means cannabis can be used to treat a wide array of pets.

Treatibles was founded in 2008 and, since then, Carella said “tens of thousands of animals” have used their products. And, while Treatibles is only marketed for horses, dogs and cats, “owners are using it on all types of animals,” she said, adding that she has received reports of rabbits, pigs, snakes and even some domesticated skunks using Treatibles products. Perhaps the most interesting story is that of Oso, a 13-year-old grizzly bear that was suffering from arthritis until he began to use Treatibles hemp oil. Now his handlers report “we’re seeing old Oso again.”

The Safety of THC for Pets

There has been much concern over an increase in THC overdoses by pets, usually dogs, living in states with legal cannabis. Research has shown a “significant positive correlation” between the rate of cannabis toxicosis in dogs and the number of cannabis licenses in those states, but that research only looks at a small sample size of 125 dogs. Unfortunately, the report which was released in 2012 found that two dogs that ate cannabis edibles died.

The American Society for the Prevention of Cruelty to Animals (ASPCA) reported that earlier this year its Animal Poison Control Center had seen a 765% increase in calls about cannabis ingestion by pets compared to the same time period the year before. Richter was clear that these cases “almost always” are dogs getting into what they weren’t supposed to and that these are not cases where “someone tried to medicate a dog and didn’t do it right.”

When it comes to those two dogs who died after eating edibles, the big question is, what did they ingest? A pet eating bud, or even hash, is a much smaller concern than a pet eating edibles. This is because edibles often include ingredients like chocolate, raisins, nuts, xylitol and given that there are savory edibles on the market, maybe even onion, garlic, or avocado — all things that are toxic to dogs and potentially cats as well.

Dogs are a special case and are more prone to THC overdoses than other animals because they have a higher concentration of THC receptors in their brains.

“Dogs have about six times the CB1 receptor density in their brains than in the human brain,” Sosnow said.  

In addition, Richter added, “there weren’t many other animals studied, but dogs had a higher concentration than the other animals studied.”

Sosnow was clear that with THC or chocolate pet owners “have to look at the dose ingested compared to the size of the dog.”

“If a Chihuahua eats a brick of bakers chocolate, they could be in trouble, but if a bigger dog eats a smaller amount of milk chocolate, there might not be an issue,” he said, adding that chocolate products, like brownies, often include nuts, contributing to a potential “combination of substances leading to the toxic effect.”

When asked about a study done by Dr. Raphael Mechoulam, which could not find a lethal dose for THC in dogs, Richter said while it is true a lethal cannabis dose for pets is unknown, some of the animals in that particular study did die. However, the reason the animals in the study died was not from a THC overdose, but because they were so high they aspirated their own vomit, got an infection from it and died from that infection.

“Even though it technically is not due to THC toxicity, it is possible for a dog to die from an edible overdose,” Richter said.

Both Richter and Carella said that if anyone is planning to use a product containing any amount of THC with a dog, it is important they get medical guidance from a veterinarian. Richter was clear that “if something is medically useful then it can also have potential negative effects.”

“A whole-spectrum CBD product with no detectable THC cannot cause static ataxia in dogs but a THC product could trigger static ataxia,” Carella said.

So while THC has been shown to have benefits to dogs as well as humans, it is best for owners to use it with caution and under the guidance of their vet.

Owners who like THC-rich edibles, especially ones that include chocolate, nuts, or raisins, should consider keeping them in the fridge, a high shelf, or in a locked container.

Even CBD Has Side Effects

Now that we’ve discussed the potential risks of THC for dogs, it’s worth going into what the potential downsides are with CBD, in both animals and humans. A 2011 study by Yamaori et al was the first to show that cannabidiol (and to a much lesser extent, THC and CBN) inhibit some enzymes in the liver, similar to grapefruit juice. The specific liver enzymes, known as CYP 450, are required for the proper metabolism of numerous commonly used pharmaceutical drugs and the inhibition of those enzymes can cause drugs to build up in the liver to potentially toxic levels. That build up can also be a good thing, if it is anticipated, and done under a doctor’s or veterinarian’s direction, as it means potentially using less of a drug to get more of an effect. Sosnow provided an example of how that can work.

“We used to use cyclosporine to treat atopy, but it was a very expensive drug,” he said. “One way to get around it was to co-administer an anti-fungal drug that would increase the time it spent in the body.”

While all the research on CBD and CYP 450 interactions has been focused on humans, the CYP 450 system is, according to Richter, “just as important in animals and the presumption is that CBD will be a CYP 450 inhibitor in animals too.”

“The system is the same in dogs but a little different in cats,” Sosnow added.

Both doctors agreed that the risks were minimal at most doses.

“I can say from a clinical standpoint I have never had an issue,” Sosnow said.

Richter mentioned a recent study that came out discussing a woman who was on CBD and an anti-seizure drug and there was an interaction but with high doses of CBD “in the neighborhood of 2,000 to 3,000 mg per day.”

Richter added pet owners should be cautious of high doses of CBD.

The Future of Cannabis for Pets

While studies have shown cannabinoids to be full of potential problems when it comes to pets there is also plenty of anecdotal and clinical evidence that shows cannabinoids could treat illnesses in animals in much the same way they do for humans.

Currently, it is not legal in any state for veterinarians to prescribe or recommend cannabis or hemp-derived medicine for pets. California passed a bill last year which would have allowed veterinarians to recommend cannabis, but, according to Richter, it did not go far enough.

“That bill got hacked apart and diluted to where it just said vets can ‘discuss’ cannabis,” he said.

Now it is up to the California Veterinary Medical Board (VMB) to define the word “discuss.” Thankfully for pet owners in California, the legislature isn’t waiting for the VMB and is charging ahead with a new bill, SB 627. Dr. Richter said the goal of SB 627 is to “put veterinarians on the same footing that [medical marijuana] doctors were put on back in 1996.”

While SB 627 unanimously passed California’s Senate, it still has to pass the Assembly and be signed into law.

“Despite things going well in the legislature the VMB is still opposed, and there is a concern that if they stay opposed the governor may have to veto it,” Richter said.

Pet owners who want to see SB 627 as law should plan to be in Sacramento on July 17 for the VMB meeting where the group is discussing SB 627. Those interested in increasing cannabis access for pets can also write their state assemblymember.

TELL US, do you have a pet you treat with THC or CBD?